Refrigerating apparatus



Nov. 25, 1930. J. F. HOFFMAN 82,687

REFRIGERATING APPARATUS Filed Aug. 1, 1927 2 Sheets-Sheet 1 INVENTOR V ATTORNEY Patented Nov. 25, 1930 UNITED: STATES PATENT OFFICE JOHN F. HOFFMAN, or OMAHA, NEBRASKA, Assronon 'ro BAKER ICE mAcnmE 00. me, or OMAHA, ,NEBaAsxa CORPORATION or NEBRASKA REFRIGERATING APPARATUS Appliliation filed August 1, 1927. Serial No. 209,690.

My invention relates to refrigerating apparatus and more particularly to apparatus of that character wherein a low boiling point liquid, such as anhydrous ammonia, is compressed and circulated through condensing ing to control supply of the refrigerating agent to the cooling coil by differential in temperature at the ends of the coil and in pressure in the supply and return lines.

It is also an object of the invention to effect the differential temperature and pressure control-with a single stage expansion of the refrigerating medium in the supply line.

In accomplishing these and other objects of the invention I have provided improved details of structure, the preferred forms of which are illustrated in the accompanying drawings,.wherein:

Fig. 1 is a diagram of arefrigerating system embodying my improvements, some of the parts being in section and magnified for better illustration.

Fig. 2 is an enlarged, central, vertical sec-v 11 high and low pressure gauges connected with the supply and return lines through the branches 12 and 13; and 14 a charging line, all in accordance with common practice, the present invention relating to improved means and apparatus for automatically controlling and regulating supply from the condenser to the coil.

The system may be controlled manually or automatically but I prefer to employ automatic control through a thermostat 15 located within the compartment served by the coil 7 andoperable on a switch 16 in the circult 17 serving the motor, so that when temperature of the compartment rises to a predetermined degree, the motor is automatically started to operatethe compressor, and when the temperature falls to the proper de gree the motor is cutoff to stop the compressor.

The unified control for the sup ly of re-' frigerating agent to the coil inclu es a valve indlcated generally 18, and comprising a valve housing body 19 and cap 20 connected by the flange bolts 21.

The body 19 has a channel 22 receiving the I threaded end 23 of the line 6 and opening lfjreiely into a chamber 24 in the top of the Extending into the chamber 24 and terminating in a ground surface flush with theftop of the body is a boss 25. Leading through the boss is "a channel 26 of the same capacity as the channel 22, having a port 27 in the top of the boss constituting the top w of the boss a valve seat.

Threaded into the outlet end of the channel 26 is a connecting line 28 constituting a continuation of the supply line 6.

The cap 20 encloses a vertical-chamber 29 having an enlarged lower portion forming a shoulder 30, and containinga spring seat 31 which rests ona diaphragm 32 separating the chamber 24 in thebody 19 from the chamber 27 in the cap 20, the periphery of the diaphra being located between the body and cap anges and held in place by the flange bolts 21.

The spring seat 31 receives the lower end of an expansion spring 33 which yieldingly urges the diaphragm to contact with thetop of the boss to close the outlet port and-interrupt flow through the supply line.

The spring at its upper end guide plate 34 engageable by a set screw 35 threaded through the upper end of-the cap and held in adjusted position by a lock nut 36. 7 Opening fromthe chamber 29 is a channel ears against a 37 receiving thethreaded end 38 of a-line 39 mally closed under tension of the spring 33 but will open under pressure of liquid in the supply line when the pressure of the liquid is suflicient to overcome combined tension of the spring and pressure in the return line, it being apparent that freedom of flow through the valve may be regulated by adjustment of tension of the spring 33.

The continuation 28 of the supply line is provided with a pressure indicator 41.

Interposed in the continuing line 28 between the indicator 41 and the coil is a temperature controlled valve indicated generally by the housing 42 and comprising a body member 43 and its cap 44. Formed in the body member is a chamber 45 closed by a lug 46 and into which the continuing line delivers through its threaded terminal 47.

Leading from the chamber 45 is a duct 48 which opens to a chamber 49 formed partly within the body 43 and partly within a cap 50 suspended from the body 43 by a bolt 51. The chamber 49 communicates through a throat 52 with a chamber 53 in the body 43, the upper part of the chamber being preferably enlarged at 54 to provide a substantial area of contact of refrigerating agent with a diaphragm 55 interposed between the body 43 and cap 44 and held in place by the bolts 56 which attach the cap 44 to the body 43.

A duct 57 leads from the chamber 53 to supply refrigerating agent from the chamber to the coil 7, the end of the coil being threaded into the outlet end of the duct.

Extending through the throat 52 into the chamber '53 is a tube 58 having a head 59 clamped against the top of the chamber 49 by a collar 60 threaded into the upper portion of the chamber above the outlet of the duct 48.

Supported on the bottom of the cap 50 about a boss 61 is an expansion spring 62 carrying a seating plate 63 which supports a valve ball 64 within the collar 60, and urges the ball to contact with the open lower end of the tube 58, thereby constituting the end of the tube a valve seat.

' Supported on the ball 64 and extending through the bore of the tube 58 is a squared pin 65.

Slidable on the upper end of the tube 58 is a sleeve 66 having a rounded head 67 engaging the diaphragm 55 at its upper face and contacted by the squared pin on its under face. The sleeve 66 is provided with port openings 68 and the tube 58 with openings 69 through which fluid may pass from the tube to chamber 53 when the valve 64 is open, as will presently be described.

The cap contains a chamber 70 enlarged at its lower end to provide the shoulder 71. Slidable in the enlarged port-ion of chamber 70 for vertical movement limited by the shoulder 71 is a cup 72, seating an expansion spring 7 3 engaging at its upper end a thrust plate 74 adjustable by set screw 75 which extends through the top of the cap and held in adjusted position by a lock nut 76. The spring 73 tends to expand the diaphragm 55 downwardly to push the pin 65 against the valve ball 64 to open the valve and provide flow through chamber 53-to the coil;

Opening through the cap 44 from the chamber 70 is a port 77 through which the chamber communicates with a channel 78 a into which is threaded the end of a line 79 leading to and communicating with an annular chamber 80 within a housing 81 on the line 9 adjacent the outlet end of the coil 7.

The port 7 7 also provides communication between the chamber 70 and the channel 82 into which is threaded the nipple 83 of a valve housing 84 containing a valve not shown but indicated by the hand wheel 85. The housing 84 is connected with the filter chamber 45 of the valve 42 whereby the refrigerating liquid admitted to the filter chamber through the continuing line 28 may be by-passed around the valve to the chamber 70 and through the line 79 into the chamber 80 to supply the chamber 80 with a quantity of such liquid and constitute such supply a thermostatic agent. 86 designates a temperature indicator on the line 79.

Assuming the parts to be constructed and assembled as described, the system may be operated as follows:

Air is first drawn from the system by operating the compressor with the charging line 14 closed, and the valves 40 and 84 open until vacuum is indicated on the gauges 1011, 41 and 86. The valves 40 and 84 are then closed and the system charged through the line 14in accordance with common practice.

At this point a pressure of, for example, 110 pounds will be indicated at 10, 50 pounds at 11, 50 pounds at 41, and a vacuum indicated at 86 because of the closure of the valve 84 after the air removal and prior to charging of the system withthe refrigerating agent.

The compressor is then put in operation and under automatic control responsive to temperature in the compartment served by the system, the refrigerating liquid being forced through the condenser and receiver into the pressure regulated valve 18 of the unified control. When this flOJV takes place pressure in the supply line is raised to, for example, 185 pounds, as indicated on gauge 10, and pressure in the return line is lowered; consequently refrigerating liquid entering the valve 18 expands the diaphragm 82 against the reduced pressure on the low pressure side, and the liquid flows beneath the diaphragm and out through the channel 26 into the connecting line 28 and to the filter chamber in the valve housing 40, without reduction in the valve 18, the gauge 41 showing the same pressure as the gauge 10 at the compressor side of the valve.

The valve 84 is then opened to permit liquid to by-pass into the upper valved chamber and through the line 79 to the chamber 80 in the housing 81 about the return line, until the gauge 86 shows a pressure of about 25 pounds less than that in the supply line. The valve 8 1' is then closed to trap the charge of liquid and retain it as a thermostaticmedium for the purposes presently. described. Such pressure of the liquid in the upper valve chamber 70 is suflicient to overcome the spring 62 and lower the ball 64 from itsseat, opening a passage from the lower valve chamber 49 through the tube 58 into the valved chamber 53 to permit flow of the refrigerating liquid through the valve into the coil 7 and back through the return line to the compressor. p

Gaseous component of the liquid trapped in the line 79 and housing 81 is subject to temperature in the return line from the coil which originally is sufiicient to expand the contents of the housing and line and exert a pressure on the diaphragm 55 sufiicient to maintain the valve open and permit flow of refrigerant to the coil. As flow continues through the coil there is a temperature exchange tending to cool the compartment served by the coil, but as the temperature in the compartment is lowered, the temperature of the refrigerating agent is also lowered until eventually such decrease in temperature reacts on contents of the housing 81 and such contents are contracted, relieving the valve 64 and permitting the valve to close. Supply of refrigerant to the coil is then cut off at the' unified control and temperature of the compartment being at a sufliciently low degree, the motor is shut off through the thermostat 15. When the compressor is stopped, pressure accumulating in the return line is transmitted to the diaphragm in the valve 18 to close the valve so that the supply line is closed at valve 18 as well as at valve 42. The sys tem then remains-idle until temperature in the compartment served by the coil rises to a' degree requiring further refrigerant. As temperature in the compartment rises, temperature of contents of the coil also rises, expanding contents of the housing 81 and opening the'temperature controlled valve {12 in the supply line, but more firmly closing the pressure controlled valve 18 in said line.

When temperature in thecompartment has risen sufiicie'ntly to operate the thermostat, the

compressor is started in operation, building up pressure in the supply line and exhausting content of the return line until pressure in the return line has reached a degree at which the valve 18 is opened under pressure in the supply line. Refrigerant then flows through the open valves and coil, back through the return line until the compartment has been brought back to the proper temperature and the valves operated as before.

It is apparent, therefore, that with the apparatus described, I provide a double control of the refrigerant supply with but a single reduction of pressure, as flow through the 1. Refrigerating apparatus, including a compressor, a cooling coil, supply and return ,1

lines connecting the compressor with the coil, and synchromzm means including separate valves in the supp y line, respectively responsive to temperature and pressure in the rei-urn line controlling flow through the supply -1ne.

2. Refrigerating apparatus, including a compressor, a cooling coil, supply and return lines connecting the compressor with the coil, independent free flow and reduction valves interposed in the supply line, one responsive to differential pressures in the supply and return lines, and the other responsive to variable temperatures in the return line.

3. Refrigerating apparatus, including a compressor, a cooling coil, supply and return lines connecting the compressor with the coil, independent free flow and reduction valves interposed in the supply line, one responsive to differential pressures in the supply and return lines, and the other responsive to variable temperatures in the return line, and a pressure gauge'on the supply line between said valves.

4. Refrigerating apparatus including a compressor, a cooling coil, a valve housing having separate chambers, one communicating with the return line, the other having a valve seat and communicating with the compressor and coil atopposite sides of said seat, a diaphragm separating said chambers and cooperative with said seat to close the line of communication from the compressor to the coil, and a spring yieldingly urging the diaphragm to said seat, the diaphragm being responsive to change in pressure in the cham ber communicating with the return line to open and close the valve. 1

In testimony-whereof I afiix my signature.

.- OHN 'F. HOFFMAN. 

